The spectro-temporal dynamics revealed in the grand average TFRs show that within the θ frequency band, a short-lasting synchronization of activity (i.e. an induced θ oscillation) occurs between about 200 ms to 600 ms. Based on visual inspection of STFT and ST grand average TFRs across MESOIs, a post-stimulus TFROI for this θ ERS was selected with lower and upper frequency bounds of 4 Hz and 6 Hz respectively, and upper and lower time bounds of 300 ms and 550 ms respectively. The corresponding pre-stimulus reference TFROI has the same frequency band as the post-stimulus TFROI, with the lower and upper time bounds of -200 ms and -100 ms respectively (the TFROIs are shown overlaid on the TFRs in Figure 1).
